#define _CRT_SECURE_NO_WARNINGS 1
#include <stdio.h>
int main()
{
	int i = 1;
	int flag = 1;
	float sum = 0;
	for (int j = 1; j <= 100; j++)
	{
		sum = sum + 1.0 / j * flag;
		flag = -flag;
	}
	printf("%f\n", sum);
	return 0;
}